Fox: Commercial Pilots 'attacked' with laser

Fox News | Greta Van Susteren

[ableChair]

Greta Van Susteren reported that a Delta pilot enroute to Salt Lake City was lazed in the cockpit this last Wednesday. Only country I know that has that hardware (for lazing bomber pilots) was the Soviet Union. Pilot reportedly required medical treatment and this was not a minor injury (weak laser) wound. More will come out to tomorrow as this story hits the print press.

[Dan Evans]

2.) 95% of the suns energy does not reach the Earth's surface in radiative form.

Post 413 shows a diagram. 51 percent of the sunlight reaches the earth in radiative form. No, not convective thermal heat -- radiation, some diffuse, some direct.

These numbers are used in climate science and take into consideration light that is blocked, absorbed or transmitted through or by clouds over the long term.

We are not interested in clouds. A laser terrorist will take the day off on overcast days.

So I've shown how, even these numbers. result in a fifty percent attenuation of red light but a better way to calculate this is to use the Beers-Lambert Law.

Db and Cboldt did that for you.

[Dan Evans]

I think this rests the case. We're not going to argue basic math now...are we? :-)

Not if you do the calculation correctly. What number do you come up with?

[KeyLargo]

Source: NASA Aviation Safety Reporting System
http://asrs.arc.nasa.gov/directline_issues/dl7_laser.htm

More than meets the Eye

Problems with Laser Light Shows

Issue Number 7 : September 1995
by Marcia Patten

"Prior to reaching NANCI Intersection...we were bombarded with multicolored laser beams coming from atop the Pan Am building. This continued until we were out of the area that the laser beams were being aimed. After turning final for runway 13, the laser beams again struck our aircraft and continued to do so until we were out of their line of sight. It appears that good sense operation of laser beams is out of hand. The damage to one's eyes, not to mention loss of night vision, can contribute to an accident." (# 89425)

Such was the surprise awaiting one Captain over New York City several years ago. Recently, though, encounters with lasers have become prevalent enough to attract media attention.

Lasers--standing for Light Amplification by Stimulated Emission of Radiation--are light beams powerful enough to cut through metal, or delicate enough to perform microscopic surgery. Apart from their scientific and medical uses, lasers are being used increasingly to produce spectacular, crowd-pleasing light shows at concerts, fairs, theme parks, and casinos.

Current Regulations
In general, commercial laser light demonstrations are regulated by the Food and Drug Administration (FDA) via its Center for Devices and Radiological Health. When a laser operator applies for a permit for an outdoor light show, the regional FAA Air Traffic Division conducts a study of the effects a light show may have upon nearby navigable airspace. The study considers many issues, including:

Quantities of traffic affected;
Traffic flow, especially arrival and departure corridors;
Locations of aviation activity that may be affected, including low-level helicopter activity;
Control jurisdiction, i.e., Tower or Center;
Coordination with local officials, i.e., airport managers, FAA Air Traffic Managers, military representatives;
Possible flight restrictions that should be imposed;
Negotiations to resolve objectionable effects, such as limiting wattage, restricting direction and or elevation of projections, weather requirements, etc.
The FAA combines its study results with information supplied by the FDA to develop power restrictions for laser use in navigable airspace. The most explicit restrictions define a horizontal and a vertical "eye-safe distance" for each display, depending on the type and intensity of the lasers used. Exposure at any closer than this distance is deemed to be potentially injurious to pilots' or passengers' eyes.

Flash Blindness
However, there is a more widespread problem associated with laser shows, that of flash blindness. A sudden flash from a laser or any other bright light causes a spot or halo to remain at the center of the visual field for a few seconds or even a minute, rendering a person virtually blind to all other visual input. At night, a flash destroys the eye's adaptation to the dark environment; partial recovery of this adaptation is usually achieved in 35 minutes, but full adaptation typically requires 4045 minutes or more. ASRS receives many reports of flash blindness being caused by various light sources, among them: lightning strikes, searchlights, aircraft static discharges or electrical short circuits, reflections from glass high-rise buildings, and even floodlights from golf course driving ranges. A First Officer flying near Miami at night reported just such an experience:

"At 10,000 feet, approximately 8 miles from downtown, a green laser was being used for a laser light show. The laser flashed directly into my eyes. I was blinded for about 2 seconds. I had trouble with near focus for about 15 seconds. My eyes 'hurt' for about 2 minutes. All normal post incident." (# 149671)
Loss of "night vision" could be particularly dangerous for a single pilot, who has no one else in the cockpit to provide assistance while initial recovery of night vision begins.

An Eyeful from "The Strip"
Las Vegas, Nevada, seems to be a hotbed of laser activity. On any evening, three or four outdoor laser light shows might pierce the skies. These shows have become a major source of pilot complaints and a major recipient of careful scrutiny by the FAA Air Traffic Management office. One crew departing Las Vegas got more than the "eyeful" usually associated with The Strip:


"[On takeoff], at approximately 500 feet AGL, a laser beam of green light struck through the right side window of my cockpit striking my First Officer in the right eye and blinding both he and I for approximately 510 seconds due to the intensity of the light beam. I immediately notified the Tower Controller [who stated] that this had become a recurring problem with the laser show coming from the top of the [hotel] in Las Vegas. We were very fortunate, because this could have been a much more serious situation had the laser struck myself as well as [my First Officer] at a more direct angle, severely blinding both of us and endangering the lives of my passengers and crew." (# 285091)
And another pilot, 90 miles south of Las Vegas, reported:

"I was flying at 31,000 feet. [The captain] saw a bright flash and said look at the laser show in Las Vegas. I looked at Las Vegas and we both got hit in the eyes with a green laser. After we turned our eyes back forward, we both noticed a green glow around the periphery of our vision. This was a momentary condition lasting no more than 10 minutes."(# 285090)
Progress
A Society of Automotive Engineers (SAE) committee, composed of FAA personnel, aviation industry representatives and others, is addressing issues of flash-blindness and its impact on safety of flight, rather than just eye-safe distance, which already is properly controlled by FDA regulations. Among the potential solutions being studied include: further limitation of laser power (wattage), restriction of laser shows to non-flight times and non-flight airspace, additional training for laser operators, enforcement action against laser operators who violate airspace regulations, and standardization of FAA handling of laser show studies. Technical advances may provide aircraft systems that can interrupt a laser's beam before it strikes the aircraft.

Forewarned is Forearmed
At present, a pilot's best defense against laser flashes is knowing where to avoid them. The locations, dates, durations, and eye-safe distances for approved displays are published in the Airport Facility Directory (AFD) for each region. Locations of light shows that have been approved after the publication of the AFD may be available only through Flight Service Stations (FSS). A glance through some of the most recent AFDs revealed quite a list of scheduled laser light show locations. Several regions noted only a few shows, but the South West region listed ten laser shows nightly. Some are temporary during the summer, or for the duration of a fair or other event; others are listed as permanent. Air carrier dispatch or base operations offices, as well as general aviation pilots, need to be in frequent contact with the local FSSs to receive the most up-to-date information on laser show activity.

Another simple defense against laser flashes is to avoid looking at them, if possible. Just as automobile drivers are advised to avoid looking directly at oncoming headlights, one airline's safety representative has recommended, "If you see the laser coming toward you, don't look right at it."

Pilots are also urged to submit reports of laser flash incidents to ASRS, and to the regional Air Traffic Management officer.

[AdamSelene235]

So, ummm, here's an easy one that any intro student should get right away. What's the integral of x exp 2?

You're funny. I started calculus at age 15 and had taken 2 years of it before I entered Georgia Tech.

1/3*x^3

High school calculus isn't what I meant by "higer math".

[SHEENA26]

I heard it was just the bright orange reflection from Kerry's fake tan.

[Cboldt]

P2 = P1/e exp (aR)

No. The equation is P2/P1 = e exp -(aR), or P2 = P1 * e exp -(aR).

[Elsie]

Paint 'em Black?


I've got an electronic welding helmet that darkness the glass in milliseconds. Would this kind of technology work to avoid this laser problem?

[ableChair]

Oh, I see. Now the equation conveniently morphs to your liking. GIVE IT UP!

[KeyLargo]

Source: Air Force Safety Magazine:
http://afsafety.af.mil/magazine/htdocs/octmag97/pg8.htm

"Blinded by the Light"

(An Old Song With New Consequences)

DOUGLAS J. FREY, SETA TEAM
Optical Radiation Division
Brooks AFB, Texas

---

The experienced commercial pilot scanned the sky ahead as he reached 5,000 feet during takeoff from McCarran International Airport near Las Vegas. Without warning, he was startled and distracted by a bright green light. Momentarily blinded, he realized he could no longer safely control the airliner. Instantly, he called on his copilot. "Take the controls--I can't see!" Fortunately, the copilot had been looking away when the light passed through the plane's cockpit. While the passengers were unaware an in-flight emergency had just occurred, if the copilot had been glancing in the same direction as the pilot, the result could have been disastrous.

From 1993 to 1995, there were more than 50 laser incidents reported by military and civilian pilots flying near Las Vegas. Similar incidents have occurred at other facilities that are close to outdoor laser light shows or near major tourist sites using lasers to attract attention. In December of last year, for example, the pilot of a Delta flight inbound for a Florida airport was temporarily blinded by a beam from a spectacular outdoor laser light show that was entertaining thousands.

Powerful lasers can cause irreparable eye damage. Scientists have developed procedures that establish minimum safe distances to prevent injuries, and the Federal Aviation Administration has established eye damage hazard zones for outdoor laser shows. Unfortunately, staying beyond this Nominal Ocular Hazard Distance (NOHD) does not solve all the safety problems for pilots. The glare and flash-blindness danger presented by entertainment (laser light shows) and commercial promotion lasers extends far beyond the established NOHD. If a pilot cannot safely control an aircraft because of momentary blindness caused by glare and flash-blindness, there may be much more than damage to one set of eyes involved--lives could be in jeopardy.

---

The Air Force predicted these problems years ago and began to explore laser exposure hazards and establish laser safety standards. The Optical Radiation Division of Armstrong Laboratory at Brooks AFB, Texas, is the leading Department of Defense element in this area, providing laser safety information to government and civilian agencies for years. In late 1994, the Air Force formed a Tiger Team under the direction of the Flight Standards Agency to address the flight hazards posed by commercial laser light shows. The Tiger Team faced two key challenges: Quantify the flight hazard distances upon which the controlling agencies could base regulatory controls, and develop methods to educate military and other aircrews to the growing flight hazards associated with lasers. As an immediate result of the team's efforts, laser hazard information is being developed for pilot refresher courses, and outdoor commercial laser show information was included in the military NOTAM system.

Because of their laser expertise and experience, Air Force scientists and engineers from the Optical Radiation Division were asked to join the Society of Automotive Engineers (Aerospace Council) G-10 Committee, the Washington DC-based group that has been charged with resolving laser dangers to flight safety. As an interim measure, the committee has prepared a safety video script and coordinated with Walt Disney Studios for production assistance.

---

Meanwhile, the Federal Aviation Administration has been working with the airline industry and with laser light show presenters to come up with a solution that will be satisfactory for all interests.

"If some of the previous illumination incidents had happened to pilots of single-seat aircraft, the results could have been disastrous," said Lt Col Leon McLin, cochair of the G-10 Committee and a researcher at the Brooks AFB laser lab. "What we want to do is take steps to minimize the risks to flight operations while still making the use of laser technology available to promoters and entrepreneurs."

---

McLin added that the people who put on laser light shows for a living have been generally cooperative and helpful in the efforts to protect safe flight operations. He warns, however, that serious laser flight hazards still exist. "The FAA considered restricting the output power of the lasers used by promoters, but instead established areas around active runways where promoters must adjust the laser output intensity of any beams that might enter those areas and present a flight safety hazard. These laser protection zones reduce the dangers presented by unintentional exposures that could result in glare and flash-blindness."

As the various agencies work to decrease laser flight hazards, it is imperative that all cockpit exposures get reported. Although there is little chance of permanent eye damage beyond NOHD warning distances, notify your local flight surgeon of any laser incidents. The flight surgeon can coordinate with bioenvironmental engineers and with the laser lab at Brooks AFB to report safety issues and verify exposure limits. Report any incidents of possible laser exposure to your flight safety office.

The possibility of laser exposure during flights is real. "The idea of flying blind during high-risk activities such as takeoff and landing is frightening. To lose a pilot or commercial air carrier because of exposure to a spectacular beam of light that was intended to entertain thousands would be a tragedy," said McLin. "We've been lucky, so far."

[AdamSelene235]

Do you understand what that equation is saying? It means that as R grows the attenuation grows exponentially

Wow, congrats on discovering Beer's law.

You have the correct form ie exp(-alpha*distance),but you are simply failing to realize that alpha is quiet small at certain, indeed, many wavelengths.

This is why there are laser radars with multiple kilometer ranges and COIL anti-missle systems that have successfully downed missles and GuideStar sodium beacons that provide a reference spot at the sodium layer, etc, etc.

Look, you know a thing or two for a nonspecialist but you really should conduct yourself with a bit more civility when discussing areas of which you obviously have no first hand experience.

[MeekOneGOP]

Oh, well ..... I see, sort of. My intention was NOT to be cryptic, but I can see where it might be confusing or ambiguous (by bad - I was in a hurry and posted in haste). But it was not intended to confuse or deceive, nor to carry a 'hidden' message.

cryp·tic [ kríptik ]

adjective 

1. ambiguous or obscure: deliberately mysterious and seeming to have a hidden meaning

2. secret: secret or hidden in some way

[Cboldt]

Oh, I see. Now the equation conveniently morphs to your liking.

No. It didn't morph under my hand. It's the same in both of the posts that I made.

I think you are funnin' with us.

[AdamSelene235]

The correct answer is 1/3 x exp 3 plus a constant...

LOL...

And btw, what was the Fourier transform of a sine wave? Surely you've googled it by now.

[Dead Dog]

Actually that was a USCG helo crew, and was in the Straits of Juan de Fuca (not realy Puget Sound)

[DB]

All right rocketman,

From the sited reference, page 4:

P(R)/P(0) = e^(-alpha * R)

Where P(R) is power at distance R and P(0) is the power at the origin.

alpha is typically 0.1 (0.43dB/km) to 1.0 (4.3dB/km) at 1.0km. Hence the referenced formula is in 1.0km distance units which is easily proven by:

e^(-.1 * 1) = 0.90484 which 10 * log(.90484) = 0.43dB/km as sited in the reference.

5 miles = 8.0km or 8 times the formula's 1.0km distance unit.

I used an alpha of 0.115 (0.5dB/km), which is slightly worse than the clear sky number in the reference.

Therefore e^(-0.115 * 8.0) = 0.3985 which is the power ratio of the source to the destination at 8.0km.

I started with a power of 50 watts at my source.

0.3985 * 50 = 19.9.

Therefore a laser passing through 5 miles of clear sky conditions would have a power level of 19.9 watts at its destination as sited in my earlier example.

In engineering decibles are often used to calculate link loss among other things.

The easier way to calculate the above is this way.

As previously stated, an alpha of 0.115 is equivelent to 0.5dB/km of attenuation which was also sited in my first example.

0.5dB * 8 (for 8.0km) = 4dB of attenuation over 8.0km.

4dB is a power ratio of: 10^(-4/10) = 0.3981.

The same number as above (without rounding errors).

You lose again.

[Bald Eagle777]

I saw this on the net a few times in the last day or so.

There was a US Military helicopter in the California region in the last year (or so?) exact date eludes me, and the pilot was injured by a laser device being transmitted (if my memory serves me correctly) from a vessel. I am not sure of the nature and extent of his injuries (eye damage etc), but he was having a REALLY hard time getting disbility from the DoD for that specific injury.

I am not sure if the article was culled from www.military.com or another clearing house, but I believe that this was a fairly recent case (in the last year or so - roughly). Dig up that story and you'll see what I am talking about.

There is a potential pattern here.

[ableChair]

Delusional and circular. Radio Shack, black helicopter crowd. See my previous posts.

[ableChair]

Surely you've googled it by now

GGGAAAHUHHH!!!

Delusional and circular. Radio Shack, black helicopter crowd. See my previous posts.